1. Field of Invention
The invention relates to a circuit stack structure. More particularly, the invention relates to a circuit stack structure of a circuit stack structure of an active component array substrate.
2. Description of Related Art
FIG. 1 is a partially top view of a known active component array substrate 10. As shown in FIG. 1, the active component array substrate 10 includes a glass substrate 20, a driver chip 30, a plurality of data lines 40 and a plurality of scan lines 50. The data lines 40, the scan lines 50 and the driver chip 30 are all disposed on the glass substrate 20. The driver chip 30 is coupled to the data lines 40 and the scan lines 50, also, the driver chip 30 is connected to a flexible printed circuit (FPC) pad area 80 through a transition line area 60 on the glass substrate 20. The transition line area 60 is disposed between the driver chip 30 and the FPC pad area 80, and wires in the transition line area 60 extend from the FPC pad area 80 to the driver chip 30, so as to exchange signals between the driver chip 30 and the FPC pad area 80. However, since the transition line area 60 has no scratch-proof design, damage by scratching on the transition line area 60 is often happened.
FIG. 2 is a cross-sectional view of FIG. 1 along a line 2-2. As shown in FIG. 2, in particular the transition line area 60 includes a circuit stack structure 70 configured on the glass substrate 20, which sequentially includes a insulation layer 71, a conductor layer (e.g., metal) 72 and a protective layer (e.g., passivation) 75 from down to up. The conductor layer 72 includes a plurality of metal wires 73 arranged at intervals on the insulation layer 71, and the protective layer 75 covers the conductor layer 72. Since a gap 74 is disposed between any two adjacent metal wires 73, after forming the protective layer 75, a convex portion 76 and a concave portion 77 are molded in the protective layer 75 respectively corresponding to the convex-concave characteristic of the metal wires 73 and the gap 74 disposed therebetween.
However, since the convex portion 76 and the concave portion 77 on the circuit stack structure 70 has various differences in shape, such as differences in height or contact area, when the protective layer 75 of the transition line area 60 is scratched by a hard object, the concave portion 77 may easily become the stress-concentrated point, or alternatively the convex portion 76 is subjected to too large friction force. As such, the wiring of the conductor layer 72 cannot be protected efficiently and the damage risk of the conductor layer 72 is increased, which further increases the manufacture or maintain cost.